The Paterson Contact Proof Printer (PTP621) is designed to proof (at least) a complete roll of 35mm film (36 exposures) on standard photographic darkroom paper of size 24x30 cm (9.5x12 inch). The Proof Printer therefore holds seven negative strokes with six exposures each.
In use the glass plate is hinged upwards and the negatives are positioned into the slots on the edges of the black mask fixed onto the under surface of the glass. The edge numbering on the film is visible through the mask allowing them to be printed onto the sheet of printing paper. A sheet of photographic printing paper is inserted emulsion side up into the contact printer. The foam pad ensures that the printing paper is in total contact with the negatives once the glass plate is clipped shut.